A methodology is suggested for a comparative analysis of energy and environmental impacts of various urban transport modes. A total emission indicator is used as a tool for integral assessment of vehicle emissions. An environmental impact factor is suggested in order to compare between the various transport modes that use different energy sources. Vehicle occupancy values, yielding equality of the specific environmental impact factors and specific energy consumption of the compared transport modes are used for the analysis purposes. This methodology is applied for a comparison between the buses and the passenger cars at various levels of service, road gradients and urban road types. The comparison results reveal that the environmental impact of the bus for driving at an urban access road falls below the one of the passenger car when the bus occupancy is 14–18 persons. Urban buses turn out to be energetically beneficial over passenger cars at occupancy values substantially lower compared with those providing a similar environmental impact.